I just picked one up from Napa, and it works good, but the diameter of the one I got from napa is much smaller than my old ac delco unit, since the sensor bottlenecks down about .5 in, will this seriously affect performance?
Before paying $174 for a new, fragile plastic sensor, I'd buy a used, bulletproof aluminum LT1 3" sensor and a Translator from turbo bob for about $50 more.
A screenless LT1 sensor flows about 200 CFM more than a stocker (probably 400 CFM more than crappy necked down aftermarket sensors) and won't break on the first backfire, dropouts, screwy readings, not hitting 255, etc, etc.
And you wil NEVER have to worry about the MAF again. ever.